• Natural Product Sciences
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• 제12권2호
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• pp.113-117
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• 2006

Quercitrin gallate was previously isolated from Persicaria lapathifolia (Polygonaceae) as an inhibitor of superoxide production. In the present study, quercitrin gallate was found to inhibit interleukin (IL)-6 production in lipopolysaccharide (LPS)-stimulated macrophages RAW 264.7 with an $IC_{50}$ value of $63\;{\mu}M$. Furthermore, quercitrin gallate attenuated LPS-induced synthesis of IL-6 transcript but also inhibited LPS-induced IL-6 promoter activity, indicating that the compound could down-regulate IL-6 expression at the transcription level. Since nuclear factor (NF)-kB has been shown to play a key role in LPS-inducible IL-6 expression, an effect of quercitrin gallate on LPS-induced NF-kB activation was further analyzed. Quercitrin gallate exhibited a dosedependent inhibitory effect on LPS-induced nuclear translocation of NF-kB without affecting inhibitory kB (IkB) degradation, and subsequently inhibited LPS-induced NF-kB transcriptional activity in macrophages RAW 264.7. Taken together, quercitrin gallate down-regulated LPS-induced IL-6 expression by inhibiting NF-kB activation, which could provide a pharmacological potential of the compound in IL-6-related immune and inflammatory diseases.

• 생약학회지
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• 제27권3호
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• pp.219-223
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• 1996

From the rachis of Cedrela sinensis A. Juss., methyl gallate, quercitrin, bis-(p-hydroxyphenyl)ether, adenosine, isoquercitrin, rutin, (+)-catechin and (-)-epicatechin were isolated and characterized by spectral data.

• 약학회지
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• 제37권3호
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• pp.306-310
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• 1993

The leaves of Cedrela sinensis have been used for food at south area in Korea and oriental medicine for treating enteritis, dysentery and itch. Kaempferol, methyl gailate, quercetin, afzelin, quercitrin, isoquercitrin and rutin were isolated from the leaves of this plant and characterized by spectral data. These compounds are reported for the first time from this plant.

• Journal of the Korean Wood Science and Technology
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• 제31권6호
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• pp.67-72
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• 2003

The leaves of D. racemosum showed strong DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and the order of the radical scavenging activity against DPPH radical is ethyl acetate (EtOAc) fraction>crude extracts>residue fraction>hexane fraction>ether fraction, under the experimental conditions. Since EtOAc fraction has highest antioxidative activity among these fractions, the isolation was performed from the EtOAc fraction of the leaves of D. racemosum and four phenolic compounds were isolated and identified as follows: methyl gallate, kaempferol, quercetin and quercitrin. The free radical scavenging activities of these compounds were 79.9%, 93.1%, 93.6% and 66.7% at 10 ㎍/ml, respectively. The IC₅₀ of compound 1, compound 2, compound 3 and compound 4 were 6.1, 4.1, 3.6 and 6.5 ㎍/ml, respectively. These compounds have higher antioxidative activity compared with reference compounds, ascorbic acid (IC₅₀ = 9.6 ㎍/ml).

• Journal of the Korean Wood Science and Technology
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• 제34권6호
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• pp.61-71
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• 2006

국내산 주요 참나무류인 신갈나무, 상수리나무, 떡갈나무, 졸참나무, 갈참나무 및 상수리나무 잎의 추출성분의 구조를 규명하고 수종 상호간의 성분의 특성 및 상호 연관성 등을 조사하였다. 신갈나무에서는 gallic acid, (+)-catechin, (-)-epicatechin, (+)-gallocatechin, kaempferol, a stragalin, astragalin-6"-O-gallate, isoquercirin, isoquercitrin-6"-O-gallate 및 myricetin 등 10종의 화합물이 단리되었고 상수리나무에서는 gallic acid, kaempferol과 quercetin이 떡갈나무에서는 gallic acid, (+)-catechin, (-)-epicatechin, (+)-galocatechin, (-)-epigallocatechin, kaempferol, quercetin, guajaverin 및 tamarixin 등 9종의 화합물이 단리되었으며 갈참나무에서는 gallic acid, caffeic acid, astragalin, quercetin과 isoquercitrin이 졸참나무에서는 gallic acid, (+)-catechin, (-)-epicatechin, kaempferol, quercitrin, isoquercitrin 및 myricetin 등 7종의 화합물이 단리되었고 굴참나무에서는 gallic acid, (+)-catechin, astragalin, astagalin-6"-O-gallate와 isoquercitrin 등 5종의 화합물이 단리되었다. Gallic aicd는 모든 수종에서 단리되어 참나무류 잎 추출성분의 지표 화합물로 이용될 수 있다.

• 생약학회지
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• 제27권3호
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• pp.212-218
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• 1996

Two phenolcarboxylic acids. five flavonoids and one hydrolysable tannin were isolated from the leaves of Acer ginnala Maxim. On the basis of chemical and spectroscopic evidence, the strutures of these compounds were established as gallic acid, ethylgallate, acertannin, quercetin, quercitrin, isoquercitrin, rutin, $quercetin-3-O-{\alpha}-_L-rhamnopyranosyl-2'-gallate$.

• 생약학회지
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• 제30권4호
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• pp.397-403
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• 1999

Tyrosinase plays an important role in the process of melanin polymer biosynthesis. Therefore, the enzyme inhibitors have been of great concern as cosmetics to have skin-whitening effects on the local hyperpigmentation. During the search for new inhibitory compounds on melanin polymer biosynthesis from natural sources, MeOH extracts of 589 higher plants were tested for the inhibitory effect on tyrosinase activity by the muschroom tyrosinase assay in vitro. Among plants tested, the leaves of Cercis chinensis exhibited potent inhibitory effect on mushroom tyrosinase activity. Subsequently seven active compounds were isolated from the ethyl acetate soluble part of acetone extract of the leaves of C. chinensis by the activity guided fractionation monitoring the inhibitory effect on tyrosinase activity. Their chemical structures were identified as $kaempferol-3-0-{\alpha}-L-rhamnoside$, quercitrin, $myricetin-3-0-{\alpha}-L-rhamnoside$, myricetin-3-0-(2'-O-galloyl)- ${\alpha}$ -L-rhamopyranoside (desmanthin), (-)-epicatechin-3-0-gallate, (-)-epigallocatechin-3-0-gallate, and methyl gallate on the basis of the speculation of spectral data and chemical reaction. Among the flavonol rhamnosides, myricetin-3-0-(2'-O-galloyl)- -L-rhamnoside(desmanthin) showed most potent inhibitory effect on tyrosinase activity and the structure of B-ring in flavonol moiety was related to the activity. (-)-Epigallocatechin-3-O-gallate having pyrogallol group in flavan-3-ol moiety exhibited more potent inhibitory effect than (-)-epicatechin-3-0-gallate having catechol group in flavan-3-ol moiety on mushroom tyrosinase activity.

• Natural Product Sciences
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• 제22권4호
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• pp.299-306
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• 2016

This study aimed to establish the quantitative method to analyze the content of peroxynitrite-scavengers belonging to polyphenols in six Korean Quercus species (Quercus mongolica, Q. dentata, Q. acutissima, Q. alienta, Q. serrata, and Q. variabilis) by HPLC. The twelve peroxynitrite-scavengers, flavanols (catechins: (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin), flavonols (kaempferol and quercetin), flavonol glycosides (astragalin, quercitrin, and isoquercitrin), flavonol acylated glycosides (astragalin 6''-gallate and isoquercitrin 6''-gallate), gallic acid and its dimer (ellagic acid) were analyzed by HPLC. Further, anti-Alzheimer's activity was assayed in a passive avoidance testusing mice by measuring the retention latency (sec), the concentration of acetylcholine (ACh), and acetylcholinesterase (AChE) activity. Simultaneous analysis of the extracts of the six Quercus leaves was achieved on a Capcell C18 column ($5{\mu}m$, $250mm{\times}4.6mm\;i.d.$) with a gradient elution of 0.05% HAc and 0.05% HAc in $CH_3CN$. In the extract of Q. mongolica leaves, the content of gallic acid (32.53 mg/g), (+)-catechin (28.78 mg/g), (-)-epicatehin (22.03 mg/g), astragalin 6''-gallate (20.94 mg/g), and isoquercitrin 6''-gallate (44.11 mg/g) and peroxynitrite-scavenging activity ($IC_{50}$, $0.831{\mu}g/ml$) were high. This extract delayed the retention latency and inhibited acetylcholinesterase activity in scopolamine-induced memory impairment of mice, suggesting that it has anti-Alzheimer's activity.

• 약학회지
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• 제40권2호
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• pp.170-176
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• 1996

A chemical examination of the aerial parts of Euphorbia pekinensis $R_{UPRECHT}$. (Euphorbiaceae) has led to the isolation of seven hydrolyzable tannins and ten fl avonoid glycosides. The former ones have been identified as gallic acid, methylgallate, 3-O-galloyl shikimic acid, 1,3,4,6-tetra-O-galloyl-${\beta}-_D$-glucose, 1,2,3,4,6-penta-O-galloyl-${\beta}-_D$-glucose, corilagin, geraniin and the latter ones as isoquercitrin, quercitrin, astragalin, afzelin, prunin, rutin, kaempferol-3-O-rutinoside, quercetin-3-O-(2"-O-galloyl)-${\beta}-_D$-glucoside and quercetin-3-O-(2"-O-galloyl)-${\alpha}-_L$-rhamnoside on the basis of chemical and spectroscopic evidence.

• 약학회지
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• 제39권6호
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• pp.600-609
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• 1995

Studies on the pharmaco-constituents from the leaves of Cercts chinensis which have been used for the treatment of inflammation, contusion, dilated blood, pain of heart and stomach, edema, etc. in Korean folk remedies were carried out. Dried leaves of the plant were extracted with MeOH. The MeOH extract was suspended in distilled water and subsequently fractionated with $Et_{2}O$ and n-BuOH. From the $Et_{2}O$ and n-BuOH fractions, six phenolic compounds were isolated and identified as myricitrin($C_{21}H_{20}O_{12}, {\;}m.p.{\;}199~200^{\circ}$. $4myricetin-3-O-{\alpha}-L-rhamnopyranoside$), kaempferol($C_{15}H_{10}O_{6}, {\;}m.p. 276^{\circ}$), quercetin($C_{15}Ha_{10}O_{7}, {\;}m.p.{\;}313~314^{\circ}$), quercitrin ($C_{21}H_{20}O_{12}, {\;}m.p.{\;}176~178^{\circ}, {\;}quercetin-3-O-{\alpha}-L-rhamnopyranoside$), gallicin ($C_{8}H_{8}O_{5}, {\;}m.p.{\;}202~203^{\circ}$. methyl gallate), gallic acid ($C_{7}H_{6}O_{5}, {\;}m.p.{\;}260~265^{\circ}) through their physico-chemical data and UV, IR, EI-MS, $^{13}C-NMR$, and $^{1}H-NMR$ analysis with authentics.